Over-voltage peaks on conductors which lead into connected equipments can happen due to various events like naturally occurring phenomenon, such as lightning strikes during thunderstorms, which induce power surges in the power lines or by man-made causes such as sudden variations in the power provided at the output due to failures of components or even occasional short circuits. Such surges can cause permanent damage to electrical equipment connected to the power line and also present great threats to human safety.
As far as concerned, the greatest problem with residual current device (RCD) is nuisance tripping of the earth leakage circuit breaker (ELCB) which is either due to the design of the RCD or due to the installation. Nuisance tripping is frequently caused by equipment leakage current or earth-potential rise (ERP) caused by lightning or high-current discharge to earth-ground. Another problem faced by the users of these equipment is that the sum-total of each legally allowed leakage current limit per connected equipment can add up to a value near the trip-threshold current, of 15 mA to 30 mA, making the ELCB or RCD nuisance-trip at the slightest addition of leakage-current.
Also, for the broadband over power line (BPL) that allows Internet data to be transmitted over utility power lines, the subscriber has to install a modem that plugs into a wall outlet. A modem surge protector is needed to protect the modem and connected computer from surges of current. However, when the modem is connected via a surge protector, they cannot function effectively with the surge protector that attenuates the data signals and if there is too high noise level or radio frequency interference (RFI) being injected into the power line.
In the present invention, a lightning and surge protection device is a safe power interface that provides minimum attenuation to data signals at one safe outlet and provides safe power for all the connected equipment via another outlet, and at the same time equipment noise is prevented from being injected into the power line. The device has an interface circuit that reduces the chances of nuisance tripping of ELCB or RCD, that are due to accumulation of leakage currents from the connected equipment.